TBM施工隧道围岩变形计算及地表沉降控制

Study on Tunnel Surrounding Rock Deformation Calculation and Surface Settlement Control of TBM Construction

城市地下隧道TBM施工中,需要严格控制地表沉降,在TBM施工期间,对地表沉降、洞内拱顶沉降、净空收敛、桩墙水平位移、桩墙竖向位移等内容需进行监控量测。为了更好的调整TBM施工参数,掌握地表、洞内、桩墙等应力和位移随时间变化的规律,建立了考虑时间效应的非线性粘弹性可变模量本构方程,通过对重庆轨道九号线砂质泥岩样进行室内试验,获得基本力学参数,并得到可变模量本构方程的计算参数。引入了广义流变理论,对地表沉降及围岩变形进行数值计算,计算结果与现场监控量测结果基本一致,地表沉降累计量变化值服从对数法则,该结论可量化指导隧道工程开挖、协同支护、动态调整TBM施工参数,预测地表沉降及围岩变形规律,为类似的工程提供指导和借鉴。

During the TBM construction of urban underground tunnels,it is necessary to strictly control the surface settlement.The surface settlement,arch settlement,clearance convergence,horizontal displacement of pile wall,and vertical displacement of pile wall need to be monitored and measured during TBM construction.In order to better adjust the TBM construction parameters and master the evolution laws of earth’s surface,hole and pile wall stress and displacement over time,the variable-compliance-type constitutive equation considering time-effect for non-linear viscoelasticity materials is established.Basic mechanical tests were conducted on sandy mudstone collected from Chongqing Railway Line 9 in the laboratory,and calculating parameters for constitutive equation were obtained.Finally,the surface subsidence and surrounding rock deformation were numerically simulated by introducing generalized rheological theory.It was found that calculation results coincided with the field monitoring data,and the cumulative values of surface subsidence obey the logarithmic law.The conclusion can quantitatively guide tunnel excavation and collaborative support and optimize TBM construction parameters.It can provide guidance and reference in predicting the surface subsidence and deformation law of surrounding rock for similar projects.